Regulation of the operon by the pleiotropic regulator AdpA in

Insertion of an apramycin resistance cassette in the operon (encoding the ClpP1 and ClpP2 peptidase subunits) affects morphological and physiological differentiation of . Another key factor controlling differentiation is the pleiotropic transcriptional regulator AdpA. We have identified a spontaneous missense mutation (−1 frameshift) in the () open reading frame in a mutant that led to the synthesis of a non-functional AdpA protein. Electrophoretic mobility shift assays showed that AdpA bound directly to promoter region. Quantitative real-time PCR analysis showed that AdpA regulated the operon expression at specific growth times. In vitro, AdpA and ClgR, a transcriptional activator of operon and other genes, were able to bind simultaneously to promoter, which suggests that AdpA binding to promoter did not affect that of ClgR. This study allowed to uncover an interplay between the ClpP peptidases and AdpA in .